An anti-T cell receptor (TCR) gamma chain variable region serum was generated and use to more precisely define the TCR gamma chains expressed at the protein level in gamma/delta TCRs, this serum allowed for the initial identification of the expression of a new type of TCRgamma chain, namely a Vgamma1.2-Cgamma2 chain. In addition, use of this antiserum showed that the molecular size diversity in Vgamma1-Cgamma4 containing gamma/delta TCRs was due mainly to the diversity in the delta chains. As a first approach to analyzing the genetic influences on the TCR gammadelta repertoire, gammadelta TCR heterodimers expressed in the spleens of different mouse strains were examined. All strains of mice studied could be categorized into one of three basic phenotypes. These phenotypes were not determined by genetic influences, but by polymorphic differences in the TCR gamma genes. Human skin was found to differ from mouse skin by the fact that it contains very few gamma/delta TCR expressing cells. Most CD3+ cells were alpha/beta TRC+, CD8+. Regions of the epidermis were found to vary significantly in the percentage of TCR bearing cells with the acrosyringial epithelium of eccrine sweat ducts having a high abundance of such cells. The alpha/beta TCR-CD3 complex is known to contain at least seven chains (alphabetagammaepsilonzeta2). Using anti peptide serum to precipitate complexes under various conditions of dissociation as well as after crosslinking. Four closely associated pairs of chains could be identified: alphabeta, zeta2, gammaepsilon and deltaepsilon. Interaction between the TCR alphabeta and either gammaepsilon or deltaepsilon could be observed in the apparent absence of other CD3 chains. Furthermore, a hierarchy in the strength of the association between the TCR and the individual CD3 chains could be distinguished: TCR epsilon > TCR delta > TCR gamma. The zeta2 dimer could only be detected in "intact" TCR=CD3 complexes. Finally, cross-linking experiments indicated a close spatial relationship between the TCR alphabeta and both the CD3-gamma and CD3-epsilon chains. Based on the observations a model for the structure of the TCR-CD3 was proposed.